Stereotype.



msasw.

WITNESSES v WA/Q jimmy/g;

J. J. 0. SMITH.

.STEREOTYPE.

APPLICATION FILED JU'LY25, 1910v Patented J an. 6, 19.14.

UV VEN TOR A TTORNEYS UNITED STATES PATENT OFFICE.

JOHN J. 0. SMITH, 0F .PASSAIC, NEW JERSEY, ASSIGNOB T0 IAUL M.HAMMALIAN, OF

HACKENSACK, NEW JERSEY.

STEREOTYP'E.

Specification of Letters Patent.

Patented Jan. 6, 1914.

To all whom it may concern:

Be it. known that I, JOHN J. 0. SMITH, a citizen of the United States,and a resident of Passaic, county of Passaic, State of New Jersey, haveinvented certain new and. useful Improvements in Stereotypes, of whichthe following is a specification.

This invention relates to stereotypes and particularly stereotypesformed of cast aluminum or of a cast metal having aluminum as itscharacteristic component.

In the accompanying drawing, which forms part of this application, thefigure 1s a perspective view of a steneotype construct ed according tomy invention.

Stereotypes at present employed are formed, either by castin type-metalagainst 1 a matrix of paper mac or by electrotypmg on a wax or similarimpression,. the electrotype shell being afterward reinforced or backedby type metal. I

A great desideratum in the of making stereotypes has been to produce astereotype of harder metal than the type-metal or electrotype platescommonly used, which are heavy in weight and soon become defaced loywear and usage. Further, since it is desired to use cuts, illustrations,type matter and the like in many different publications in different andremote places and at as nearly the same time as. possible, the cost oftransportation, particularly where sent by mail, as is frequently done,is, owing to the weight of the ordinary type-metal stereotypes, an itemof considerable expense, which my invention is intended to overcome.

I have found that aluminum, or an alloy consisting principally ofaluminum, possesses characteristics and properties rendering iteminently suitable and desirable for stereotypes. Among such propertiesmay be mentioned its ability to make a good casting of the characterrequired for stereotypes; its rigidity, hardness and durability;

its ability to make a good printing surface which will wear well-andpermit comparatively roughusage, and which will not oxidizeand will besubstantially acid proof; and its lightness in weight;

The relatively high melting temperature of aluminum, and thedifficulties encountered in preparing a mold to meet the conditionsrequired for making stereotypes of this metal, and the impossibility ofmaking elec if trotypes of aluminum the frame.

adhesive surface to have heretofore pre eluded its use for stereotypes.

To successfully produce stereotypes of this metal, the moldingcomposition used must not only possess the requisite characteristics ofwithstanding the heat of the molten metal to be cast therein when themold is formed without cracking or checking, but it must also possesssuch tenacity that it will, when set, withdraw absolutely clean from thepatterns and without distortion. Furthermore, it must be of such acharacter that it will enter the finest detail and lines of the designand reproduce a sharp and perfect impression. It will be obvious thateven the finest cracks or a slight amount of shrinking or Warping willdestroy the mold and make it impossible toprocure a good castingtherefrom, particularlywhen it is considered that themetal is cast inthe molds under pressure.

Molds heretofore employed for producing metal castingsand stereotypes donot satisfy the above requirements.

To produce aluminum stereotypes in the best manner now known to me, .Ipreferably employ a molding composition of my own invention formed ofclay, asbestos fiber and plaster of Paris, (which composition is fullydescribed in Letters Patent of the United States, No. 950,355, issued tome) and then proceed as follows: A mold frame is provided having sidesadapted to inclose the molding space and the patterns, and a plate,preferably of steel, supported by said sides and extending over thespace inclosed thereby. Said plate, which, as aforesaid, is part of themold frame, is perforated or provided with a plurality of apertures,through which the molding material is poured as hereinafter stated. Saidframe is preferably shallow so as to take very little molding material,and so as to form a thin mold, the strength and rigidity of which isderived from the metallic frame. The frames 1 have employed are not overthree-eighths of an inch thick, including the perforated plate. For usewith the said frame I provide a base of somewhat greater dimensions thanThis base may he of wood or any other suitable material or may form thetopv of a table or "work bench. On its upper surface, this base isrovided with a nonwhich'the molding mato become confined in the cavitiesand lines.

terial Lwill not stick, as, for example, a

' smooth rubber sheet.

as may be desired, and according to the dimensions of the mold frameemployed. The patterns will preferably be arranged with sufiicient spacebetween them to allow for the necessary gates or sprues, as will beunderstood'by any one skilled in the molding or casting art.

- Having arranged the patterns and the blocks on plates forming thegates and sprues for the mold, I coat the faces thereof with a thin filmof separting medium to in-.

sure a clean separation of the mold from the patterns. For this purposeI preferably employ good sperm oil, applied to the sur-' face of thepatterns with a stiff brush so as to reach and coat every cavity anddeep line of the pattern. This coating of oil or the like, whilenecessary to insure clean separation of mold from patterns, has thedisadvantage of increasing the tendency of air of the design, therebypreventing the plaster composition from entering and thus producing adefective mold. The repellent or antagonistic character of the oiledsurface against the water of the fluid plaster composition tends to keepthe latter from flowing into and occupying the deeper recesses and linesof the pattern. It will be understood that for stereotypes the design orpattern is fine and intricate, presenting many hundreds of smallrecesses and cavities on a surface less than fifty square inches, and inorder to produce a successful stereotype a faithful reproduction ofevery line and cavity of the design is required. Agitation of theplaster composition, after it has been cast upon the pattern and whilestill fluid, has been proposed, but this is only effective in designswhich do not present the intricacies of detail possessed by stereotypesand is ineffective for such moldings. Furthermore, if agitation beattempted. for the purpose of removing the confined air in the cavities,as, for instance, by applying a brush to drive the same out, the oilfilm becomes removed in places where reached by the brush, and thisresults in the mold composition sticking to the pattern and producingdefects. To overcome these difliculties, I wet or moisten the oiledsurface of the pattern with a fluid which will lie uniformly thereon andnot be either repellent or antagonistic to the water of the moldingcomposition. For such fluid I have found wood alcohol to give good andsatisfactory results. Having therefore coated the patterns withoil, asabove stated, I then apply wood al ohol to the oiled surface- This ispreferably done by applying the wood alcohol in a fine spray by means ofan atomizer. Care should be taken to apply no more alcohol than isrequired to wet the oiled surface, as an excess of alcohol would belikely to delay the setting or hardening of the mold. a The mold-frameis then placed over the prepared patterns and the same is held inposition either by arranging Weights around its edges or by clamping itto the base,-or in any convenient way. The molding composition havingbeen prepared, is now poured into the mold or frame through theperforations or apertures therein. Sufficient of the molding compositionis poured in to completely fill the interior of the mold frame and torise through the apertures or perforations and to overflow the same.When the composition has partially set, say, in about ten minutes, thesurplus composition is removed by striking it off, by means of a stickor bar, level with the top of the perforations or apertures. In thisway, the

frame becomes embeddedin and forms part of the mold.- After about tenminutes more, the composition sets ,sufliciently hard to permit the moldtobe removed from the base board and patterns. This removal of the moldshould be done with care and I prefer- ,ably provide means for liftingthe frame equally at all points. The mold may now be placed at onceinto. a drying oven of any suitable kind, heated by gas or other meansof heat, to a temperature of about.600 F. The,, molds sustain thisdegree of heat without any danger of cracking or any other injury. Theyare left in the oven for a period of from two to three hours, at the endof which time the moisture and water are all expelled therefrom. Afterhaving been dried, the molds are ready for the casting operation. Itwill be apparent that the mold is constituted by the thin layer ofmolding composition which carries the design or impression, togetherwith the perforated moldframe. The latter gives great stiffness,rigidity and strength to the mold, not only protecting it from damagebut enabling it to resist the pressure to which his subjected in thecasting operation. 7

In a co-pending application, Serial No.

518,319 (now Patent No. 965,242, dated July 26, 1910) I have fullydescribed and illustrated my said process for making molds forstereotypes, and in another co-pending application, Serial No. 487,169(now Patent No. 965,241, dated July 26, 1910), Ihave fully described andillustrated apparatus for making stereotypes, which process andapparatus are applicable to making stereotypes of aluminum.

When the molds are ready for casting'as above stated, fluid metal isforced into the molds under pressure. I preferably employ a machine orapparatus for so casting the metal. ltlachines or apparatus of this typehaw. long been known and have been in vented by myself and others. (Seefor instance, United States Letters Patent, No. 70,038 granted toMichael Smith, October Q2. 1864'; No. 477,231 granted to myself andVictor E. Smith, June 21st, 1892- and No.

591.430 granted to myself October 12th,?

1997.) In machines of this character, the fluid metal .is forced intothe molds under what is substantially the equivalent of hydraulicpressure, which forced the metal into the fine details and lines of thedesigns, enabling, thereby a perfect casting to be obtained.

I thus produce a stereotype of aluminum, or of an alloy thereofconsisting principally of aluminum, of a high degree of perfection, in arapid and economical manner.

Having: described my invention, I claim:

1. A cast metal stereotype composed of aluminium.

A. cast metal stereotype having aluminium as its characteristiccomponent.

3. A cast metal stereotype made of an alloy of which alun'linium is theprincipal component.

In witness whereof, I have hereunto set my hand to the foregoingspecification in the presence of two subscribing witnesses.

' JOHN J. C. SMITH.

\Vitnesses CHARLES FELTUAN, J. MoLAUonLIN.

